How to calculate the trigonometric function value of the special angle of mathematics in grade three?
According to some mathematical laws.
For example, a right triangle with an angle of 45 is an isosceles right triangle. If the length of two right-angled sides is 1, the length of the hypotenuse is √2.
So sin 45 = cos 45 =1√ 2 = √ 2/2, TAN 45 = COT 45 = 1.